void *recv_thread(void *arg)
{static int cnt = 0;while(1){sem_wait(&recv_sem); pthread_mutex_lock(&recv_mutex);struct msg_buf *msg = msg_mbox;msg_mbox = msg->next;pthread_mutex_unlock(&recv_mutex);//处理msg消息int retval = sendto(msg->sockfd, msg->buf,msg->len, 0,(struct sockaddr *)&(msg->their_addr), msg->sin_size);printf("Received %d from %s\n%s\n",++cnt,inet_ntoa((msg->their_addr).sin_addr),msg->buf);put_msgbuf(msg);}
}

int main(int argc,char *argv[])
{int sockfd;                     /* 数据端口 */struct sockaddr_in my_addr;     /* 自身的地址信息 */int  retval;if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {perror("socket");exit(1);}/* 设置地址可复用 */int option = 1;setsockopt( sockfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option) );my_addr.sin_family = AF_INET;my_addr.sin_port = htons(MYPORT); /* 网络字节顺序 */my_addr.sin_addr.s_addr = INADDR_ANY; /* 自动填本机IP */bzero(&(my_addr.sin_zero), 8); /* 其余部分置0 */if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(my_addr)) == -1) {perror("bind");exit(1);}/***　其它初始化　* */server_init();/* 主循环 */while(1) {struct msg_buf     *recvmsg = get_msgbuf();size_t len = sizeof(recvmsg->buf);char *buf  = recvmsg->buf;struct sockaddr_in their_addr; int sin_size;memset(buf,len,0);retval = recvfrom(sockfd, buf, len, 0,(struct sockaddr *)&their_addr, &sin_size);printf("%s\t%s\n",inet_ntoa(their_addr.sin_addr),buf);if (retval == 0) {perror ("recvfrom");close(sockfd);break;}////封装消息recvmsg->their_addr = their_addr;recvmsg->sin_size = sin_size;recvmsg->sockfd = sockfd;recvmsg->len = retval;//发送给某消息处理
        msg_post(recvmsg);}return 0;
}